Low temperature polycrystalline semiconductor device and manufacturing method thereof

ABSTRACT

A semiconductor device include a substrate, a buffer layer formed on the substrate, a channel layer formed by an intrinsic polycrystalline silicon layer on the buffer layer, polycrystalline source and drain by non-intrinsic silicon formed on both sides of the polycrystalline silicon layer, a source electrode and a drain electrode formed on the polycrystalline source and the drain, a gate electrode corresponding to the channel layer, and an NiSi2 contact layer located between the source and the source electrode and between the drain and the drain electrode.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY

The present application is a divisional of U.S. application Ser. No.17/028,341, filed on Sep. 22, 2020, which is a continuation ofPCT/KR2019/002511 filed on Mar. 5, 2019, which claims priority to andthe benefit of the filing dates of Korean Patent Application Nos.10-2018-0034097, filed on Mar. 23, 2018, and 10-2018-0130238, filed onOct. 29, 2018, in the Korean Intellectual Property Office, thedisclosures of which are incorporated herein in their entirety byreference as if they are fully set forth herein.

TECHNICAL FIELD

The present disclosure relates to a polycrystalline MOS device and amanufacturing method thereof, and more particularly, to a CMOS using anLTPS TFT.

BACKGROUND

A low temperature polycrystalline silicon thin film transistor (LTPSTFT) having high mobility and high reliability is appropriate as a pixelswitching device of an AM-OLED display that is widely used in a mobiledevice such as a smartphone.

Excimer laser annealing is mainly used for crystallization of silicon tomanufacture the LTPS TFT. Such an LTPS TFT has high mobility and highreliability but may not maintain crystal grain uniformity of a certainlevel in a large area display in which a large number of TFTs arearranged.

MIC and MILC technologies that have been studied a lot in an LTPStechnology cause contamination of Ni elements and a leakage current in adevice and thus are not used in actual products. An ELA technology isaccompanied by expensive equipment and high process cost, and metalinduced crystallization (MIC) and metal induced lateral crystallizationmethods using a metal catalyst are inexpensive in terms of cost but makequality of a polysilicon thin film low.

SUMMARY

According to one or more embodiments of the present disclosure, asemiconductor device manufactured by a method of manufacturing asemiconductor device is provided. The method includes steps of (i)forming a buffer layer of an insulating material on a substrate, (ii)forming a seed layer of catalyst material containing Ni on the bufferlayer, (iii) forming, on the buffer layer, an amorphous intrinsicsilicon layer for forming a channel, (iv) forming, on the amorphousintrinsic silicon layer, a non-intrinsic silicon layer for forming asource and/or drain, (v) forming a metal layer on the non-intrinsicsilicon layer, and (vi) performing metal induced crystallization (MIC)process producing NiSi₂ by catalytic reaction of Ni and Si forcrystallization of the amorphous intrinsic silicon layer and theamorphous non-intrinsic silicon layer, and activation of the amorphousnon-intrinsic silicon layer to form a conductive area, and forming acontact layer by the NiSi₂ being reached between the conductive area andthe metal layer while the crystallization is progressed. Thesemiconductor device includes a substrate, a buffer layer formed on thesubstrate, a channel layer formed by an intrinsic polycrystallinesilicon layer on the buffer layer, polycrystalline source and drain bynon-intrinsic silicon formed on both sides of the polycrystallinesilicon layer, a source electrode and a drain electrode formed on thepolycrystalline source and the drain, a gate electrode corresponding tothe channel layer, and an NiSi₂ contact layer located between the sourceand the source electrode and between the drain and the drain electrode.

In at least one variant, the non-intrinsic polycrystalline source anddrain include a first non-intrinsic silicon layer contacting both sidesof the channel layer, and a second non-intrinsic silicon layer providedon the first non-intrinsic silicon layer. The first non-intrinsicsilicon layer further extends toward the gate than the secondnon-intrinsic silicon layer to form a lightly doped drain (LDD).

In another variant, a PMOS area and an NMOS area are divided on thesubstrate. A p-type TFT includes source and drain by a p-typenon-intrinsic silicon layer is formed in the PMOS area, and an n-typeTFT including source and drain by an n-type non-intrinsic silicon layeris formed in the NMOS area.

In another variant, a PMOS area and an NMOS area are divided on thesubstrate, and a p-type TFT including source and drain by a p-typenon-intrinsic silicon layer is formed in the PMOS area, and an n-typeTFT including source and drain by an n-type non-intrinsic silicon layeris formed in the NMOS area.

According to one or more embodiments of the present disclosure, a methodof manufacturing a semiconductor device includes steps of (i) forming abuffer layer of an insulating material on a substrate, (ii) forming aseed layer of catalyst material containing Ni on the buffer layer, (iii)forming, on the buffer layer, an amorphous intrinsic silicon layer forforming a channel, (iv) forming, on the amorphous intrinsic siliconlayer, a non-intrinsic silicon layer for forming a source and/or drain,(v) forming a metal layer on the non-intrinsic silicon layer, and (vi)performing metal induced crystallization (MIC) process forcrystallization of the amorphous intrinsic silicon layer and theamorphous non-intrinsic silicon layer, and activation of the amorphousnon-intrinsic silicon layer to form a conductive area.

In at least one variant, the manufacturing method further includesforming a catalytic reaction control layer between the seed layerformation operation and the silicon layer formation operation.

In another variant, the seed layer is formed of at least one selectedfrom the group consisting of NiCxOy, NiNxOy, NiCxNyOz, NiCxOy:H,NiNxOy:H, NiCxNyOz:H, NixSiy, and NixGey.

In another variant, the non-intrinsic silicon layer is formed so that afirst non-intrinsic silicon layer, in contact with an amorphous siliconlayer for forming a semiconductor channel, has a lower dopingconcentration than a second non-intrinsic silicon layer formed on thefirst non-intrinsic silicon layer.

In another variant, after the MIC process, a pattering operation offorming a source electrode and a drain electrode corresponding to theintrinsic silicon layer by patterning the metal layer and thenon-intrinsic silicon layer.

In another variant, the patterning operation further includes steps of(i) exposing the first non-intrinsic silicon layer in a channel areabetween the source electrode and the drain electrode by patterning themetal layer and the second non-intrinsic silicon layer, (ii) forming aninsulating spacer on inner sides of the source electrode and the secondnon-intrinsic silicon layer thereunder and on inner sides of the drainelectrode and the second non-intrinsic silicon layer thereunder, whereina lower end of the spacer covers the first non-intrinsic silicon layerby a preset width, and (iii) etching a portion of the firstnon-intrinsic silicon layer that is not covered with the spacer.

In another variant, a PMOS area and an NMOS area are arranged in thenon-intrinsic silicon layer. The silicon layer formation operationfurther includes forming a p-type non-intrinsic silicon layer and ametal layer thereon in the PMOS area and forming an n-type non-intrinsicsilicon layer and a metal layer thereon in the NMOS area.

In another variant, a PMOS area and an NMOS area are arranged in thenon-intrinsic silicon layer. The silicon layer formation operationfurther includes forming a p-type non-intrinsic silicon layer and ametal layer thereon in the PMOS area and forming an n-type non-intrinsicsilicon layer and a metal layer thereon in the NMOS area.

In another variant, a PMOS area and an NMOS area are divided on thenon-intrinsic silicon layer. The silicon layer formation operationfurther includes forming a p-type non-intrinsic silicon layer and ametal layer thereon in the PMOS area and forming an n-type non-intrinsicsilicon layer and a metal layer thereon in the NMOS area.

In another variant, a PMOS area and an NMOS area are divided on thenon-intrinsic silicon layer. The silicon layer formation operationfurther includes forming a p-type non-intrinsic silicon layer and ametal layer thereon in the PMOS area and forming an n-type non-intrinsicsilicon layer and a metal layer thereon in the NMOS area.

In another variant, a PMOS area and an NMOS area are divided on thenon-intrinsic silicon layer. The silicon layer formation operationfurther includes forming a p-type non-intrinsic silicon layer and ametal layer thereon in the PMOS area and forming an n-type non-intrinsicsilicon layer and a metal layer thereon in the NMOS area.

In another variant, a PMOS area and an NMOS area are divided on thenon-intrinsic silicon layer. The silicon layer formation operationfurther includes forming a p-type non-intrinsic silicon layer and ametal layer thereon in the PMOS area and forming an n-type non-intrinsicsilicon layer and a metal layer thereon in the NMOS area.

Provided are a semiconductor device capable of forming a high-qualitypolycrystalline silicon thin film at a low process cost and a method ofmanufacturing the same.

Provided are also an LTPS semiconductor device which may have a largearea by effectively forming an LTPS and a method of manufacturing thesame.

In a method of manufacturing an LTPS semiconductor device according toan aspect of the present disclosure, an LTPS is formed by using, as aseed, a thin film made of at least one selected from the groupconsisting of NiCxOy, NiNxOy, NiCxNyOz, NiCxOy:H, NiNxOy:H, NiCxNyOz:H,NixSiy, and NixGey.

According to an aspect of the present disclosure, a method ofmanufacturing a semiconductor device, includes steps of: (i) forming abuffer layer of an insulating material on a substrate; (ii) a see layerformation operation of forming, on the buffer layer, a seed layer of atleast one selected from the group consisting of NiCxOy, NiNxOy,NiCxNyOz, NiCxOy:H, NiNxOy:H, NiCxNyOz:H, NixSiy, and NixGey; (iii) asilicon layer formation operation of forming an amorphous silicon layeron the seed layer; and (iv) a crystallization operation of crystallizingthe amorphous silicon layer by a catalytic action of Ni by thermallytreating the amorphous silicon layer.

The method may further include forming a catalytic reaction controllayer between the seed layer formation operation and the silicon layerformation operation.

The silicon layer formation operation may include steps of: (i) forming,on the buffer layer, an amorphous intrinsic silicon layer for forming achannel; (ii) forming, on the amorphous intrinsic silicon layer, anon-intrinsic silicon layer for forming a source/drain; and (iii)forming a metal layer on the non-intrinsic silicon layer.

The non-intrinsic silicon layer may be formed so that a firstnon-intrinsic silicon layer, in contact with an amorphous silicon layerfor forming a semiconductor channel, has a lower doping concentrationthan a second non-intrinsic silicon layer.

The method may further include, after the crystallization operation, apattering operation of forming a source electrode and a drain electrodecorresponding to the intrinsic silicon layer by patterning the metallayer and the non-intrinsic silicon layer.

The patterning operation may include steps of: (i) exposing the firstnon-intrinsic silicon layer in a channel area between the sourceelectrode and the drain electrode by patterning the metal layer and thesecond non-intrinsic silicon layer; (ii) a spacer formation operation offorming an insulating spacer on inner sides of the source electrode andthe second non-intrinsic silicon layer thereunder and on inner sides ofthe drain electrode and the second non-intrinsic silicon layerthereunder, wherein a lower end of the spacer covers the firstnon-intrinsic silicon layer by a preset width; and (iii) etching aportion of the first non-intrinsic silicon layer that is not coveredwith the spacer.

A PMOS area and an NMOS area may be divided on the non-intrinsic siliconlayer, and the silicon layer formation operation may include: forming ap-type non-intrinsic silicon layer and a metal layer thereon in the PMOSarea and forming an n-type non-intrinsic silicon layer and a metal layerthereon in the NMOS area.

According to another aspect of the present disclosure, a semiconductordevice may include: a substrate; a buffer layer formed on the substrate;a channel layer formed by an intrinsic polycrystalline silicon layer onthe buffer layer; polycrystalline source and drain by non-intrinsicsilicon formed on both sides of the polycrystalline silicon layer; asource electrode and a drain electrode formed on the polycrystallinesource and the drain; a gate electrode corresponding to the channellayer; and an NiSi₂ contact layer located between the source and thesource electrode and between the drain and the drain electrode.

The non-intrinsic polycrystalline source and drain may include: a firstnon-intrinsic silicon layer contacting both sides of the channel layer;and a second non-intrinsic silicon layer provided on the firstnon-intrinsic silicon layer, where the first non-intrinsic silicon layermay further extend toward the gate than the second non-intrinsic siliconlayer to form a lightly doped drain (LDD).

A PMOS area and an NMOS area may be divided on the substrate, a p-typeTFT including source and drain by a p-type non-intrinsic silicon layermay be formed in the PMOS area, and an n-type TFT including source anddrain by an n-type non-intrinsic silicon layer may be formed in the NMOSarea.

According to an example embodiment, a high-quality primarily orientedLTPS may be obtained, and contamination of Ni may be negligibly lowered.When crystallization of an a-Si thin film is induced by using anamorphous thin film seed layer made of at least one selected from thegroup consisting of NiCxOy, NiNxOy, NiCxNyOz, NiCxOy:H, NiNxOy:H,NiCxNyOz:H, NixSiy, and NixGey, Ni is precipitated to a thin filmsurface and thus does not remain in a TFT channel. Crystallinity of LTPSis greater than or equal 98%, a surface RMS is smaller, particleuniformity is high, a large area may be expanded, manufacturing cost islow, and productivity is high. Also, a method according to an exampleembodiment may reduce a photolithographic process by at least twostages, compared to an existing method of manufacturing a LTPSsemiconductor device. In addition, activation of source and drain isperformed simultaneously when a silicon channel is crystallized withoution implantation for an existing source-drain doping process, and inparticular, may serve as a mass production process for a-Si TFTs,thereby enabling manufacturing facilities to be shared.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A illustrates an operation for forming a buffer layer on asubstrate, according to the present disclosure.

FIG. 1B illustrates an operation for forming an amorphous seed layer onthe buffer layer, according to the present disclosure.

FIG. 1C illustrates an operation for forming an intrinsic silicon layeron the seed layer, according to the present disclosure.

FIG. 1D illustrates an operation for forming a non-intrinsic siliconlayer and a metal layer on the intrinsic silicon layer, according to thepresent disclosure.

FIG. 1E illustrates an operation for performing metal inducedcrystallization of the silicon layers, according to the presentdisclosure.

FIG. 1F illustrates an operation for patterning the metal layer and thenon intrinsic silicon layer, according to the present disclosure.

FIG. 1G illustrates an operation for forming a spacer for coveringcrystallization of the strips, according to the present disclosure.

FIG. 1H illustrates an operation for partial removing a part of thenon-intrinsic silicon layer, according to the present disclosure.

FIG. 1I illustrates an operation for forming a gate insulating layer,according to the present disclosure.

FIG. 1J illustrate an operation for forming an interlayer dielectriclayer having a contact hole, according to the present disclosure.

FIG. 2A illustrates an operation for forming a buffer layer and anamorphous seed layer on a substrate, according to the presentdisclosure.

FIG. 2B illustrates an operation for forming an intrinsic silicon layeron the seed layer, according to the present disclosure.

FIG. 2C illustrates an operation for forming a p-type non-intrinsicsilicon layer and a first metal layer on the intrinsic silicon layer,according to the present disclosure.

FIG. 2D illustrates an operation for patterning the p-type non-intrinsicsilicon layer on the seed layer, according to the present disclosure

FIG. 2E illustrates an operation for forming a n-type silicon layer anda second metal layer, according to the present disclosure.

FIG. 2F illustrates an operation for forming silicon islands on the seedlayer, according to the present disclosure

FIG. 2G illustrates an operation for inducing crystallization of thesilicon islands, according to the present disclosure

FIG. 2H illustrates an operation for patterning to form source and drainelectrodes, according to present disclosure.

FIG. 2I illustrates an operation for removing a part of thenon-intrinsic layer between the source and drain electrode, according tothe present disclosure

FIG. 2J illustrates an operation for forming a gate electrode, accordingto the present disclosure

FIG. 2K illustrates operation for forming an interlayer dielectric layerhaving contact holes and metal pads thereon, according to the presentdisclosure.

DETAILED DESCRIPTION

Hereinafter, example embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings.However, embodiments of the present disclosure may be modified intovarious forms, and the scope of the present disclosure should not beconstrued as being limited by the embodiments described below. Theembodiments of the present disclosure may be interpreted as beingprovided to further completely explain the spirit of the presentdisclosure to one of ordinary skill in the art. Like reference numeralsin the drawings denote like elements. Various elements and areas in thedrawings are schematically drawn. Therefore, the spirit of the presentdisclosure is not limited by the relative size or spacing drawn in theaccompanying drawings.

Although the terms first, second etc. may be used herein to describevarious elements, these elements should not be limited by these terms.These terms are only used to distinguish one element from anotherelement. For example, a first element may be termed a second element andconversely, the second element may be termed the first element withoutdeparting from the scope of the present disclosure.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments. As used herein, the singular forms are intended to includethe plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “have” when used in this specification, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meanings as commonly understood by oneof ordinary skill in the art to which example embodiments belong. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

When a certain embodiment may be implemented differently, a specificprocess order may be performed differently from the described order. Forexample, two processes described in succession may be performedsubstantially simultaneously or may be performed in an order opposite tothe described order.

As such, variations from the shapes of the illustrations as a result,for example, of manufacturing techniques and/or tolerances, are to beexpected. Thus, example embodiments should not be construed as limitedto the particular shapes of regions illustrated herein but may be toinclude deviations in shapes that result, for example, frommanufacturing. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items. The term“substrate” as used herein may mean a substrate itself or a stackedstructure including a substrate and a predetermined layer or film formedon the surface thereof. As used herein, “the surface of the substrate”may mean an exposed surface of the substrate itself, or an outer surfaceof a predetermined layer or film formed on the substrate. What isdescribed as “above” or “on” may include not only those directly on incontact but also non-contact above.

Hereinafter, a method of manufacturing a MOS FET and a complementarymetal-oxide semiconductor (CMOS) applying the same according to anexample embodiment will be described in detail with reference to theaccompanying drawings. In the following description, silicon is referredto as a channel material of a transistor, but according to anotherexample embodiment, other semiconductor materials such as germanium inaddition to silicon may be applied as a substitute material.

FIG. 1 schematically shows main processes of processes of manufacturinga metal oxide silicon field effect transistor (MOS FET), according tothe present disclosure.

As shown in FIG. 1A, a buffer layer 11 is formed of an insulatingmaterial on a substrate 10. An electronic device structure formed in apreceding process may be present underneath the buffer layer 11. Thesubstrate 10 may be a glass substrate or a plastic substrate. The bufferlayer 11 may be formed of an insulating material used for manufacturinga semiconductor device, for example, may be formed of one of SiO₂, SiNx,SiONx or AlOx.

As shown in FIG. 1B, an amorphous seed layer 12 is formed to a thicknessof several nanometers on the buffer layer 11. An atomic layer deposition(ALD) method may be applied to form the seed layer 12, and a constituentmaterial of the seed layer 12 is one of NiCxOy, NiNxOy, and NiCxNyOz orone of NiCxOy:H, NiNxOy:H, NiCxNyOz:H including hydrogen (H). Inaddition to the above materials, the material of the seed layer 12 maybe NixSiy or NixGey.

As shown in FIG. 1C, an intrinsic silicon layer 13 is formed bydepositing intrinsic a-Si on the seed layer 12. Here, a thickness of theintrinsic silicon layer 13 may be adjusted within a range of about 50 nmto about 150 nm. As a selective element, between the seed layer 12 andthe silicon layer 13, a catalytic reaction control layer 12 a may beformed to suppress or control violent reaction between an Ni catalystmaterial and silicon due to direct contact between the seed layer 12 andthe silicon layer 13. Before the silicon layer 13 is formed, thecatalytic reaction control layer 12 a may be formed to a thickness ofseveral angstroms to several nanometers through which the Ni catalystmaterial may permeate. The maximum thickness of the catalytic reactioncontrol layer 12 a is limited to the thickness through which the Nicatalyst material may pass to the silicon layer 13 thereon. Thecatalytic reaction control layer 12 a may be formed of a normalinsulating material such as SiO₂, SiNx, SiONx or AlOx.

As shown in FIG. 1D, a doped or non-intrinsic silicon layer 14 dopedwith a p-type or n-type dopant and a metal layer 15 are sequentiallystacked on the intrinsic silicon layer 13. Among the dopants, the p-typedopant includes at least one selected from the group consisting of B,Al, Ga, and In, and the n-type dopant includes at least one selectedfrom the group consisting of P, Sb, and As.

Here, the non-intrinsic silicon layer 14 may be formed as a single layerdoped with a p-type or n-type dopant at a preset concentration and,according to the present embodiment, may include first and secondnon-intrinsic silicon layers 14 a and 14 b having different dopingconcentrations. For example, the doping concentration of the firstnon-intrinsic silicon layer 14 a in contact with the intrinsic siliconlayer 13 is lower than that of the second non-intrinsic silicon layer 14b thereon, and the first and second non-intrinsic silicon layers 14 aand 14 b are crystallized into polycrystalline silicon in a subsequentheat treatment process. The metal layer 15 may have a single layer ormultilayer structure. According to the present embodiment, the metallayer 15 may have a sandwich structure having a stack structure ofTiN/Al/TiN.

After the metal layer 15 is completed as described above, an a-Si islandto be used as a channel of a TFT is formed by patterning an intrinsicsilicon layer formed in a transistor area, in particular, formed on theentire surface of the substrate 10.

As shown in FIG. 1E, metal induced crystallization (MIC) is performedthrough heat treatment. According to this heat treatment, a-Si of theamorphous silicon layer 13 on the seed layer 12 is crystallized, andthus, the silicon layer 13 formed of poly-Si oriented in (111) directionis obtained. In this process, Ni and Si of the seed layer 12 react witheach other to produce NiSi₂, NiSi₂ reaches the uppermost non-intrinsicsilicon layer 14 after passing through the silicon layer 13 to form acontact layer 12′ between the non-intrinsic silicon layer 14 and themetal layer 15, and nickel is precipitated to the outside of thenon-intrinsic silicon layer 14 after crystallization is completed. Also,in the MIC process, the non-intrinsic silicon layer 13 is crystallizedtogether, and a dopant of the non-intrinsic silicon layer 14 isactivated to form a conductive area.

According to the example embodiment described above, source/draindoping, which is performed by existing ion implantation, may be achievedthrough deposition of the non-intrinsic silicon layer 14 and the MICprocess without a separate ion implantation process. At the currentstage, the source and drain are not yet isolated, and a source S and adrain D are obtained through a subsequent patterning process of thenon-intrinsic silicon layer 14.

As shown in FIG. 1F, the metal layer 15 and the second non-intrinsicsilicon layer 14 b underneath the same are patterned by using aphotolithographic method, thereby forming, on both sides of a siliconsemiconductor channel area C, the source S and the drain D, and a sourceelectrode 15 a and a drain electrode 15 b corresponding thereto.According to this patterning, a portion of the first non-intrinsicsilicon layer 14 a covering the intrinsic silicon layer 13 is exposed onthe surface of the silicon semiconductor channel area C.

Here, an extended area of the first non-intrinsic silicon layer 14 athat is not covered with the second non-intrinsic silicon layer 14 bcorrespond to a lightly doped drain (LDD) having lower conductivity thanthe second non-intrinsic silicon layer 14 b.

As shown in FIG. 1G, a spacer 16 for covering an upper portion of thefirst non-intrinsic silicon layer 14 a is formed on facing sides of thesource electrode 15 a and the drain electrode 15 formed at a presetheight above both sides of the intrinsic silicon layer 13. The spacer 16is formed not only on sides of the source electrode 15 a and the drainelectrode 15 b but also on a side of the second non-intrinsic siliconlayer 14 b thereunder, and a lower end thereof covers the surface of thefirst non-intrinsic silicon layer 14 a. The spacer 16 may be formed ofan insulating material such as SiO₂ or SiNx, and the spacer 16 coveringthe LDD area may be obtained through entire surface deposition and etchback processes of SiO₂ or SiNx.

As shown in FIG. 1H, a portion of the non-intrinsic silicon layer thatis not covered with the spacer 16 between the source electrode 15 a andthe drain electrode 15 b is removed. Through this etch back process, anextended portion 14 a′ of the first non-intrinsic silicon layer 14 acorresponding to the LDD area is located underneath the spacer 16.

As shown in FIG. 1I, a gate insulating layer 17 is formed on the entiresurface of the source electrode 15 a and the drain electrode 15 b, andthe intrinsic silicon layer 13 exposed therebetween, and a gateelectrode 18 is formed in a channel area between the source electrode 15a and the drain electrode 15 b.

Here, the gate insulating layer 17 may be formed of one of SiNx, SiO₂,AlOx, or HfOx. The gate electrode 18 may be obtained by entire surfacedeposition and patterning of MoW.

As shown in FIG. 1J, an interlayer dielectric (ILD) layer 19 having acontact hole 19 a is formed on the gate electrode 18, and electrode padsPs, Pg, and Pd that are electrically connected to the source electrode15 a, the drain electrode 15 b, and the gate electrode 18, respectively,through the contact hole 19 a are formed on the ILD layer 19.

In the above-described process, merely a major part has been describedwithout describing a method of manufacturing a complete MOS to aid inunderstanding of the example embodiment.

Hereinafter, an embodiment of a method of manufacturing a CMOS for adisplay will be described with reference to FIGS. 2A through 2K.

As shown in FIG. 2A, a buffer layer 21 and an amorphous seed layer 22are sequentially formed on a substrate 20 in which a PMOS area and anNMOS area are defined (divided). The buffer layer 21 may be formed ofone of SiO₂, SiNx, SiONx, or AlOx.

The seed layer 22 is formed to a thickness of several nanometers.Thermal atomic layer deposition (ALD), plasma enhanced thermal atomiclayer deposition (PE-ALD), pulsed plasma enhanced chemical vapordeposition (PECVD), or the like may be used to form the seed layer 22. Aconstituent material of the seed layer 22 is at least one selected fromthe group consisting of NiCxOy, NiNxOy, NiCxNyOz, NiCxOy:H, NiNxOy:H,NiCxNyOz:H, NixSiy, and NixGey. The material of the seed layer 22material may include crystallization of silicon at a lower temperaturethan existing NiOx, thereby obtaining high-quality polycrystallinesilicon.

As shown in FIG. 2B, an intrinsic silicon layer 23 to be used as achannel of a transistor is formed of amorphous silicon on the seed layer22. Here, a thickness of the intrinsic silicon layer 23 is about 50 nmto about 150 nm. A catalytic reaction control layer 22 a as describedabove may be selectively formed. In other words, the catalytic reactioncontrol layer 22 a is a selective element and may be formed before theintrinsic silicon layer 23 is formed. The catalytic reaction controllayer 22 a may be formed of a normal insulating material such as SiNx,SiONx, or AlOx

As shown in FIG. 2C, a p-type non-intrinsic silicon layer 24 including ap-type dopant and a first metal layer 25 are sequentially formed on theintrinsic silicon layer 23. Here, the p-type non-intrinsic silicon layer24 may be formed of a plurality of layers having different dopingconcentrations.

In the present embodiment, the p-type non-intrinsic silicon layer 24includes a first non-intrinsic silicon layer 24 a and a secondnon-intrinsic silicon layer 24 b thereon. A doping concentration of thesecond non-intrinsic silicon layer 24 a is relatively higher than thatof the first non-intrinsic silicon layer 24 a. The first metal layer 25may have a multilayer structure in which the same or different types oflayers are stacked. According to the present embodiment, the first metallayer 25 may have a sandwich structure having a stack structure ofTiN/Al/TiN.

As shown in FIG. 2D, the p-type non-intrinsic silicon layer 24 ispatterned from the metal layer 25. Here, merely the PMOS area remains,and the p-type non-intrinsic silicon layer 24 is removed by etching fromthe first metal layer 25 in a remaining area. For this, for a detailedexample, the PMOS area to be protected is covered with a mask layer suchas photoresist and then etched, thereby removing portions of the p-typenon-intrinsic silicon layer 24 and the first metal layer 25, includingthe NMOS area, outside the PMOS area.

After selective etching as described above, cleaning is performed, andthen a stack structure, including an n-type non-intrinsic silicon layer26 and a second metal layer 27 thereon in the NMOS area, is formed onthe intrinsic silicon layer 23 in the NMOS area.

As shown in FIG. 2E, the n-type non-intrinsic silicon layer 26 and thesecond metal layer 27 are formed in the NMOS area other than the PMOSarea. This process includes a deposition process of a non-intrinsicsilicon material and metal on the entire surface, and a process ofremoving n-type non-intrinsic silicon and metal thereon in a portionexcluding the NMOS area.

As shown in FIG. 2F, a stack structure for manufacturing a p-type TFTand an n-type TFT, respectively, in the PMOS area and the NMOS areaobtained through the processes described above is patterned, therebyforming silicon islands 23 a and 23 b to be used as channels of thep-type TFT and the n-type TFT, from the amorphous non-intrinsic siliconlayer 23.

As shown in FIG. 2G, MIC is performed by heat treatment to formpolycrystalline islands 23 a′ and 24 b′, which are (111) oriented, fromthe silicon islands 23 a and 23 b. In this process, not only intrinsicsilicon but also non-intrinsic silicon is crystallized. According tothis crystallization, Ni and Si of a catalytic layer present under theintrinsic silicon layer 23 reach with each other to form NiSi₂, andNiSi₂ rises to the top of a silicon layer and contacts the first andsecond metal layers 25 and 27 to function as a contact layer betweensilicon and metal.

In the present embodiment, heat treatment may be performed in a normalfurnace and may also be performed in a furnace to which anelectromagnetic field is applied.

As shown in FIG. 2H, the first and second metal layers 25 and 27 arepatterned to form source electrodes 25 a and 27 a and drain electrodes25 b and 27 b in the PMOS area and the NMOS area, and, under a channelarea C therebetween, first non-intrinsic silicon layers 24 a and 26 aare exposed.

Above both sides of the intrinsic silicon layer 23, a spacer 29 coveringthe first non-intrinsic silicon layers 24 a and 26 a is formed on facingsides of the source electrodes 25 a and 27 a and the drain electrodes 25b and 27 b formed at a preset height in a source area S and a drain areaD. The spacer 29 is formed not only on sides of the source electrodes 25a and 27 a and the drain electrodes 25 b and 27 b but also on sides ofthe second non-intrinsic silicon layers 24 b and 26 b thereunder, and alower end thereof covers preset widths of surfaces of the firstnon-intrinsic silicon layers 24 a and 26 a providing an LDD area. Thespacer 29 may be formed of an insulating material such as SiO2 (orSiNx), and the spacer 29 covering the LDD area may be obtained throughentire surface deposition and etch back processes of SiO2 (or SiNx).

As shown in FIG. 2I, the first non-intrinsic silicon layers 24 a and 26a that are not covered with the spacer 29 are removed to expose surfacesof polycrystalline silicon islands 23 a′ and 23 b′ underneath the same.Here, the surfaces of the polycrystalline silicon islands 23 a′ and 23b′ are exposed by a self-align etching method using, as a mask, thesource electrodes 25 a and 27 a, the drain electrodes 25 b and 27 b, andthe spacer 29.

As shown in FIG. 2J, a gate insulating layer 30 is formed over the PMOSarea and the NMOS area, and each of gate electrodes 31 a, 31 b is formedin a channel area of each of the PMOS are and the NMOS area.

Here, the gate insulating layer 30 may be formed of one of SiNx, SiO₂,AlOx, or HfOx. The gate electrodes 31 a, 31 b may be obtained throughentire surface deposition and patterning of MoW.

As shown in FIG. 2K, an ILD layer 32 having a contact hole 32 aconnected to the source electrodes 25 a and 27 a, the drain electrodes25 b and 27 b, and gate electrodes 31 a, 31 b is formed. Here, metalpads 33 s, 33 g, 33 d, 34 s, 34 g, and 34 d are formed to complete aCMOS having a PMOS TFT and an NMOS TFT. Thereafter, a process of formingadditional elements of a device to which these CMOSs are applied may beperformed.

In the above process, each of an intrinsic amorphous silicon layer and anon-intrinsic silicon layer including an n-type or p-type dopant may bedeposited in an independent cluster chamber.

Materials of source/drain electrodes and a gate electrode as describedabove are associated with control of a threshold voltage Vth of a deviceand thus need to appropriately combined. Also, an LDD by a firstnon-intrinsic silicon layer is associated with control of a leakagecurrent and control of the threshold voltage Vth, and thus, whether ornot the LDD is to be formed may be determined by the controls of theleakage current and the threshold voltage Vth. For example, an LDD maynot be formed in a PMOS.

A method of manufacturing an LTPS TFT and a CMOS applying the sameaccording to the present disclosure as described above performscrystallization by basically using amorphous Ni-based oxide as acatalyst. As a seed layer formed of Ni-based oxide for this, one ofNiCxOy, NiNxOy, and NiCxNyOz in addition NiOx may be applied or one ofNiCxOy:H, NiNxOy:H, and NiCxNyOz:H including hydrogen (H) may beapplied. Also, the seed layer may be formed of NixSiy or NixGey.

Through this process, an LTPS TFT (111)-oriented on a glass substrate ora plastic substrate may be obtained, and a CMOS may also be formed byusing the same.

In addition, when forming a polycrystalline silicon channel, anintrinsic silicon layer for a silicon channel and intrinsic silicon fora source and a drain, i.e., silicon including an n-type dopant or ap-type dopant, is formed. Therefore, without an existing separate ionimplantation process, crystallization of intrinsic silicon, andcrystallization and activation of source and drain by non-intrinsicsilicon are simultaneously achieved in an MIC process.

Also, non-intrinsic silicon forming the source and drain are formed in amultilayer. Here, a dopant concentration of a first intrinsic siliconlayer contacting a silicon channel may be lower than a dopantconcentration of a second non-intrinsic silicon layer thereon, and thefirst non-intrinsic silicon layer may extend closer to the center of achannel than the second non-intrinsic silicon layer, therebyimplementing an LDD having low conductivity.

A method of manufacturing a semiconductor device according to an exampleembodiment has been described with reference to the embodiments shown inthe drawings to aid in understanding the present disclosure, but this ismerely an example. It will be understood by one of ordinary skill in theart that various modifications and other equivalent embodiments arepossible therefrom. Therefore, the technical scope of the presentdisclosure should be defined by the appended claims.

What is claimed is:
 1. A semiconductor device manufactured by a method of manufacturing a semiconductor device, the method comprising: forming a buffer layer of an insulating material on a substrate; forming a seed layer of catalyst material containing Ni on the buffer layer; forming, on the buffer layer, an amorphous intrinsic silicon layer for forming a channel; forming, on the amorphous intrinsic silicon layer, a non-intrinsic silicon layer for forming a source and/or drain; forming a metal layer on the non-intrinsic silicon layer; performing metal induced crystallization (MIC) process producing NiSi₂ by catalytic reaction of Ni and Si for crystallization of the amorphous intrinsic silicon layer and the amorphous non-intrinsic silicon layer, and activation of the amorphous non-intrinsic silicon layer to form a conductive area, and forming a contact layer by the NiSb being reached between the conductive area and the metal layer while the crystallization is progressed; the semiconductor device comprising: a substrate; a buffer layer formed on the substrate; a channel layer formed by an intrinsic polycrystalline silicon layer on the buffer layer; polycrystalline source and drain by non-intrinsic silicon formed on both sides of the polycrystalline silicon layer; a source electrode and a drain electrode formed on the polycrystalline source and the drain; a gate electrode corresponding to the channel layer; and an NiS₂ contact layer located between the source and the source electrode and between the drain and the drain electrode; wherein the non-intrinsic polycrystalline source and drain comprise: a first non-intrinsic silicon layer contacting both sides of the channel layer; and a second non-intrinsic silicon layer provided on the first non-intrinsic silicon layer, wherein: the first non-intrinsic silicon layer further extends toward the gate than the second non-intrinsic silicon layer to form a lightly doped drain (LDD).
 2. The semiconductor device of claim 1, wherein: a PMOS area and an NMOS area are divided on the substrate; and a p-type TFT including source and drain by a p-type non-intrinsic silicon layer is formed in the PMOS area, and an n-type TFT including source and drain by an n-type non-intrinsic silicon layer is formed in the NMOS area. 